Artificial textile material and method of making same



Patented Feb. 22, l dh TAES any c1 2,1lll8,836

AR'llKlFlICllAL 'lllEX'lflilLlE IMTERW ANED lilllE'lElflIQilD 691i MAKING SAW/RE William Whitehead, Qumberland, Mid assignor to Celanese florpcration of America, a corporation of Delaware ii (Claims.

This invention relates to the preparation and manufacture of yarns, filaments, fabrics and other articles from artificial materials such as the organic esters of cellulose wherein at least 5 a part of the filaments employed are made sus ceptible to ready saponification, and more specifi cally to fabrics wherein a part of the filaments contained therein are made susceptible to ready saponification in such a manner that the same may be saponified in the piece without substantial effect upon the untreated parts of the filaments.

An object of the invention is the economic and expeditious production of textile materials containing yarns and filaments of an organic ester of cellulose, which materials are so prepared that any degree of saponification may be imparted thereto or to localized parts thereof by treating the same in baths which normally wduld not saponify similar organic esters of cellulose.

A further object of my invention is the proddetion of-textile fabrics which have been treated in localized parts or which contain yarns of organic esters of cellulose which have been peri- Odically treated with a saponifying or sensitizing agent such that the same when treated with a mild saponifying agent are further saponified in the sensitized portion while leaving the urisensitized portion substantially unaffected. A still further object of the invention is to produce yarns and filaments which formed into textile fabrics may be caused to have a high degree of shrinkage, adapting them for use in the'formation of crepe style fabrics. Other objects of the invention will appear from the following detailed description.

In the manufacture of cross dyed fabrics containing yarns containing organic esters of cellulose it is often desired to have certain parts of 40 each yarn saponified such that it may be dyed with a dyeing material having an affinity for cotton, while other portions of the same yarn have an affinity only for the dyeing materials which dye organic derivatives of cellulose; In

such fabrics it is also'further desired that the degree of saponification may be such as to give any desired depth of color when employing the dyeing-material having an aflinity for cotton. Formerly, in making up such textile fabrics, the so yarns of organic esters of cellulose were periodically or random saponified to the desired depth and then woven into fabrics. Heavily saponified yarns of organic esters of cellulose in a wet condition are much weaker than the original yarns prior to saponification. Further, the saponified great extent prior to weaving but the same are etched or slightly saponified over the. portion of their area which it is desired shall be saponified 15 in the finished article. Thus, these yarns are not materially weakened nor difier appreciably from each other intensil Strength and elongation either when in a wet state or dry state. After the yarns are formed into a fabric the 20 etched or partially saponified portion which, for the purpose of this inventionwill be termed sensitized portion, may be developed by treat-- ment in baths that normally have no effect upon organic derivatives of cellulose but which afiect 25 the sensitized portion and further saponify them. By regulation-of the time, temperature and concentration of this developing bath, any higher degree of saponification desired may be imparted to those yarns or segments of yarns that 30 were sensitized, without producing any appreciable efifect or change in affinity for dyes of the unsensitized yarns or segments of yarns.

By employing this invention textile fabrics may be formed containing yarns or segments of 5 yarns having any desired degree of saponification, which saponiflcation may be imparted. to the yarns or segments of yarns after the same are formed into a fabric. In this manner yarns which are periodically or random sensitized may 40 be sold to manufacturers who may weave'the same or form the same into special types offabrics, which fabrics may be treated in such a way as to remove the sensitizing material and then dye the fabrics evenly with dye material having 4,5 an afiinity' for organic esters of cellulose or, at the option of the manufacturer, the fabrics after being formed may be developed to any desired greater extent, that is, the sensitized portion of the yarns or filaments may be saponified to any greater extent suchwthat they will be susceptible only to dye materials having an affinity for cotton or such that they may be dyed by either type of dye material such as the dye materials having an affinity for organic esters of cellulose and those dye materials having an ailinity for cotton material.

In accordance with my invention I partially and lightly saponify yarns and filaments containing organic esters of cellulose to sensitize the same, which sensitizing may cover the entire yarn or filament or may be applied thereto intermittently, periodically or at random and then, either before or after forming the yarns and filaments into fabrics, I treat the same in a bath having a pH value from v8 to 11 or more for the purpose of developing or further saponifying the yarn or only that part of the yarn which has been sensitized. Also in accordance with my invention I partially and/or lightly saponify localized areas of warps or fabrics and then treat the resulting fabrics in a bath having a pH value of from 8 to 11 or more for the purpose of developing the treated areas without substantially affecting the unsaponified areas or yarns.

This invention is applicable to the treatment of yarns or filaments of any suitable ester of cellulose that is capable of being partially and totally saponified by the treatment with bases as, for example, yarns and filaments formed from the nitrates of cellulose or the organic esters of cellulose, for instance, cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate. The yarns or filaments containing these materials may be formed by either the wet or dry methods of spinning and may contain besides the derivative of cellulose base material, effect materials such as pigments, dyes, lakes, fillers, plasticizers and lubricants.

After the yarns or filaments have been sensitized in accordance with this invention they may be formed into fabrics in any suitable manner.

Sensitized yarns or filaments may be employed as the warp threads of a fabric or the .weft threads of a fabric or both warp and weft threads. These yarns and filaments so sensitized may be used alone or they may be doubled with yarns and filaments made of other materials such as unsensitized yarns or threads of organic derivatives of celluiose, wool, cotton, silk, flax, etc. or the same may be woven into fabrics along with such other yarns or threads in any suitable manner. The fabrics may be formed from these threads or combination of threads by weaving, warp knitting, circular knitting, netting and knotting.

By selection of a suitable sensitizing material or the amount of sensitizing material applied to the yarns or filaments or fabric containing organic esters of cellulose, yarns and filaments may be made which are adaptable to warp knitting and circular knitting as well as weaving and without any substantial difliculties as to the formation of poor stitch shape, pin holes and like effects and the same passes readily through guides, needles, etc. and is capable of having]. uniform tension maintained thereon. The yarns I and filaments of organic esters of cellulose during any winding operation may be partially saponified over their entire area or periodically or intermittently. by applying to such yarns and filaments a saponifying agent. The saponifying agent thus employed, or, as it maybe called, the sensitizing agent, has a saponifying action that may be very slight or carried to such an extent that the loss in weight of the yarn at those parts sensitized is from 2 or less to '7 per cent of their weight. The sensitized materials may be applied to the yarn during the winding operations by passing the yarns over a wick or roller that dips into a bath containing any suitable basic compound having a pH value of between 10.5 to 14. Any other suitablemethod of applying the sensitizing material may be employed such as passing the yarn through a bath containing a saponifying agent or hank dipping yarns in such a bath. In place of sensitizing the yarn along its entire length, the advantage of crossdyeing effects may be produced by periodically sensitizing the yarn. This periodical sensitizing of the yarn may be accomplished by intermittently contacting the yarn as it' is being wound with a roller or wick which will furnish to those parts of the yarn contacted a suitable saponifying agent. Further, periodic, intermittent or random saponification or sensitization of the yarn may be had by various methods of dipping the yarn into such solutions as will partially saponify same. For instance, hanks of the yarn may be clamped between members which protect certain parts of the yarn only and, while held in the clamps, dipped in baths containing sensitizing material. I

The sensitizing material is a base material or a solution of a base material having a pH value of 10.5 to 14. Any suitable basic solution may be employed for this purpose such as an aqueous solution or an alcoholic solution of an alkali hydroxide, for instance, sodium hydroxide or potassium hydroxide, an aqueous solution of ammonium hydroxide, a salt of a strong base such as ammonia or alkali and a weak acid such as the organic acids, organic compounds having a basic reaction, etc. Examples of salts ofa strong base and an organic acid which may be employed for this invention are sodium acetate, potassium acetate, etc. bases that may be employed as the sensitizing agent are the primary, secondary and tertiary amines, for instance, ethanol amine, methanol amine, di-methanol amine, di-ethanol amine, tri-methanolamine and tri-ethanol amine. Also the quarternary ammonium bases may be employed, for instance, tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, etc. These materials may be applied to the yarn from aqueous solutions, which solutions may be of any suitable concentration such that the pH value of the solution is'above 10. In the treatment of yarns which are to be used in certain types of machines wherein they of necessity must pass through small guide eyes and needles, it is some times advisable to select a sensitizing agent which, when applied to the yarn and after reaction with the acid radicle thereof, forms a salt, the crystals of which do not interfere with the passing of the yarn through said guides. The length of treatment that the materials receive in such solutions is preferably limited such that the materials are not saponified to any great extent. For instance, it is found preferable in most cases to limit the first saponification or sensitization in time, temperature and concentration such that the yarns at those places treated lose only about 2 to '7 per cent of their. weight. Obviously the concentration, temperature and duration of treatment of the yarns will vary according to the sensitizing agent employed to produce this limited degree of saponification.

After the yarns have been sensitized as above Examples of organic described, that is, to such an extent that they bath or a second bath to saponify the places of the yarns sensitized to any desired extent. The second or developing bath preferably consists of a basic solution having a pH value of between 8 to 10.5 and the duration and temperature of treatment so regulated that the-unsensitized portions of the yarn, if any, are unaffected by the second treatment. The preferable method of carrying out this second step of saponification is to treat the fabric in a bath containing from to grams or more per litre of soap in an aqueous media at a temperature from 70 C. to boiling which treatment would not have an appreciable saponifying action on unsensitized material. The duration of treatment in the soap bath will depend upon the sensitization, the soap and the temperature of the bath and may vary between 10 minutes and one hour, depending upon the degree of saponificationdesired. Although soap solutions are normally preferred for developing and further saponifying the sensitized yarns, any basic solution having a pH value between 8 and 10.5 may be employed and for this purpose dilute solutions of the reagents named above as sensitizing agents may be employed. By varying the concentration, the time and temperature of the developing or second saponifying bath, the sensitized parts of the yarn may be caused to lose as much as 20 per cent or more of their weight without any appreciable saponification being apparent on the unsensitized portion of the yarn.

The sensitized or periodically sensitized yarn, produced by partially saponifying over intermittent lengths of the yarn during the winding operation, may be further saponified in after treatments of the yarn or fabric produced therefrom, such further saponification affecting only the saponified or sensitized places with substantially no saponification to the unsaponified or unsensitized'places. This further saponification or second saponification may be desired to obtain greater depth in shade than where only a light periodic saponification has been applied originally or even to obtain such a degree of saponification that the saponified places substantially or completely resist dyestuffs which normally dye cellulose acetate and like yarns but'which have no afiinity for cotton and the regenerated cellulose yarns. This further saponification or development may be effected by treating the yarn in hydrolyzing baths of moderate pH value such as, for example, 9 or 10, which normally have subs stantially no hydrolyzing or very little and slow bufiering substances.

up to the boiling points thereof.

reaction is more rapid when the temperature of the bath is elevated, for example, to 80 C. and The increase in saponification is appreciable in such baths even within such times as 10 to 30 minutes.

If it is not desired to increase the saponification of yarns sensitized in accordance with this invention but it is desirable to treat the goods in soap and similarly reacting baths, then the goods may be pretreated by washing the sensitizing material away from the fabric first with water which removes the acetate or other salt of the base formed on the yarn during the sensitizing operation. Also, the subsequent saponification of the yarn when treated in soap baths, etc. may be prevented by washing in dilute acids prior to entering the scouring bath containing the soap. By thus treating the yarn either by washing or by a treatment in a dilute acid the whole of the yarn is brought to such a state that any light basic treatment, such as a soap bath applied thereto, will not appreciably aiTect the previously sensitized or saponified portions more than the unsensitized or unsaponified portions.

In sensitizing the yarn it is not necessary that appreciable saponification be obtained to result in this increase in saponification in the saponified places by after treatments. However, in the initial step of saponifying or sensitizing any degree of .saponification may be applied to the yarn. This invention, however, is particularly applicable to the sensitizing of the yarn during the winding operation such as when the yarn is being formed at the metier or during a twisting or rewinding operation and is of particular advantage in that the yarn may be lightly saponified, thereby not substantially altering its uniformity in any respect. In such an operation where the sensitizing material is applied during the winding operation, it is obviously of advantage that substantial results may be obtained by applying a rather limited quantity of saponifying material to the yarn. In such application during the winding operation the application of a limited supply of saponifying material produces sharp lines of demarcation between the saponified portion and the unsaponified portion and the yarn may be sufficientlydried prior to being wound up that there is .nosmearing or blurring due to the contact of one portion of the yarn to another portion of the yarn on the spool or bobbin. Although the yarns and filaments are only slightly saponified during the sensitizing operation on treating such yarns with soap and similarly reacting baths, saponificationoevelops in the places sensitized to a sufiicient extent within commercial times to render the yarns where they have been sensitized susceptible to dyeing with dyestufis having an affinity for cotton and like dyestuffs, while portions of the yarn not subjected to the sensitizing material or wetted thereby do not sa-ponify in such baths suinciently that they will absorb dyestuffs having an affinity for cotton.

, As an aid to illustrating this invention and not as limitations, the following examples are given,

Example I An acetone soluble cellulose acetate yarn is that the sapo-nification has progressed to a weight loss of 10 per cent and the afiinity for cotton colors correspondingly increased.

Ezample II Example I is repeated using instead of soap in the second saponification step a molecular equivalent of sodium acetate. The yarn in this case is found to have progressed to a weight loss of 8.4 per cent.

Example III Example I is repeated using a molecular equivalent of the 10 grams per litre soap of sodium hydroxide which is then titrated to a pH value of 9.5 preferably with a weak acid or salt which is acid by hydrolysis such as ammonium sulphate. The yarn is found to progress to a weight loss of 8.5 and develop a proportionate increased affinity for cotton colors;

Example IV A bath containing 20 grams per litre soap solution is employed and the yarn sensitized as in Example 1 and is treated for about four hours at a temperature between 90 and 95 C. The sensi- 'tized or prior saponified yarn increases in saponification to the extent of a weight loss of approximately 25 per cent. The yarn in this case absorbs cotton and similar colors but resists dyestuffs normally having an aflinity for cellulose acetate yarns.

- Example V Example 4 is repeated using yarn which has been caused to periodically contact with a furnishing device furnishing a sensitizing material containing a, 20 per cent solution of sodium hydroxide instead of continuously sensitizing the yarn. The portions which have not contacted or beenlwetted by the sensitized material are not sufliciently saponifled by the hot soap solution treatment to produce an afllnity for cotton dyestufis, the weight loss of the unsensitized portion being about'one per cent or less while the weight loss in those portions which were previously sensitized is about 25 per cent of the original weight of the yarn. These heavily-sensitized places resist dyestuffs having an afllnity for organic esters of cellulose but absorb cotton and similar dyestuffs.

Example VI Example 5 is repeated instead of using yarns sensitized with sodium hydroxide, the yarn during a winding operation is periodically contacted with per litre soap solution bath for one hour at 90 C.

produces a weight loss on the yarn at those parts contacted with the sodium acetate and'develops an appreciable sensitivity to cotton dyestuffs.

While in the foregoing specification I have cited specific instances and examples, it is not my intention that the scope of the invention should be limited thereby as many modifications of this process may be employed without departing from the spirit of my invention. Numerous eifects may be obtained on the yarn in winding,,for example, one or more windings may be involved and one or more depths of saponification obtained in the winding process or as it may be stated one or more degrees of sensitivity may be produced during the winding operation and later these may 'be increased by after treatments of the yarn or fabric derived therefrom. For example, it is obvious that it is possible to increase the saponification to such an extent by these after treatments that one portion of the yarn saponified or sensitized to one degree may be increased in saponificati on to produce a resistance to dyestuffs having an aflinity for organic esters of cellulose yet take on dyestuifs having an aflinity for cotton while another portion not sensitized as much may only be increased in its sensitivity to cotton dyestuffs and not develope a resistance to dyestuffs having afilnity for organic esters of cellulose.

Further, while I have cited winding processes for effecting initial saponification, the process is nevertheless applicable to other treatments or methods of saponifying the yarn which may involve dipping or immersing hanks in baths containing the alkali with portions of the yarn protected by clamps, wax or other repellent devices or materials. Similarly hank printing may be employed, or for that matter the fabric may be printed itself, with the sensitizing agent, it only being necessary that the products of the reaction of the saponification or sensitization are left on the yarn or fabric and not prescoured before the yarn or goods are processed in the developing or saponifying process. This invention is particularly applicable to the printing of designs and patterns on a warp, which warp when woven into a fabric may be more completely saponified by the treatment herein described, yet the printing of the warp does not sufliciently change the tensile strengths of the yarn nor their elongation to substantially afiect the evenness of the warp for the production of uniform fabrics.

. Having described my invention, what I desire to secure by Letters Patent is:

1. Process for locally saponifying filaments, yarns, fabrics and like materials having a basis of organic ester of cellulose, which comprises removing from selected areas of the material a small proportion of its acidyl content by pretreatment with analkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and

subsequently completing the desired saponifica-.

tion of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an alkaline substance which is less alkaline than that employed in the pretreatment and which has substantially no saponifying action on the areas of the ma-- terial which have not been pretreated.

"2. Process for. locally saponifying filaments, yarns, fabrics and like materials having a basis of cellulose acetate, which comprises removing from selected areas of the material a small proportion of its acetyl' content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponification of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an alkaline substancewhich is less alkaline than that employed in the pretreatment and which has substantially no saponifying action on the areas of the material which have not been preterated. g

3. Process for the production of fabrics containing yarns of locally saponified organic ester of cellulose, which comprises removing from selected areas of yarns of organic ester of celluderived from the pretreatment, with an alkaline substance which is less alkaline than that employed in the pretreatment and which has substantially' no saponifying action on the areas of 4 the yarn which have not been pretreated.

4. Process for the production of fabrics containing yarns of locally saponified cellulose acetate, which comprises removing from selected areas of yarns of cellulose acetate a small proportion of their acetyl content by pretreating the yarns at intervals along their length with an alkaline saponifying agent, making up a fabric containing said pretreated yarns, and completing the desired saponification of the pretreated areas by treating the fabric, while said yarns still contain reaction products derived from the pretreatment, with an alkaline substance which is less alkalinethan that employed in the pretreatment and which has substantially no saponifying action on the portions of the yarn which have not been pretreated.

a Process for locally saponifylng filaments, yarns, fabrics and like materials having a basis of cellulose acetate, 'which comprises. removing from selected areas of the material a small proportion of its acetyl content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponification of the pretreated areas by, treating the material, while it still contains reaction products derived from the pretreatment, with a medium of pH value between 8 and 10.5 which has substantially no saponifying action on the areas of the material which have not been pretreated.

6. Process for locally saponifying filaments, yarns, fabrics and like materials having a basis of cellulose acetate, which comprises removing from selected areas part of the material a small proportion of its acetyl content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponification of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an aqueous solution of a soap which has substantially no saponifying action on the areas of the material which have not'been pretreated.

7. Process for locally saponifying filaments, yarns, fabrics and like materials having a basis of cellulose acetate, which comprises removing from selected areas of the material a small proportion of its acetylcontent by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponification ofthe pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an aqueous solution of sodium acetate which has substantially no saponifying action on the areas of the material which have not been pretreated. v

8. Process for the production of fabrics containing yarns of locally saponified cellulose acetate, which comprises removing from selected areas of yarns of cellulose acetate a small proportion of their acetyl content bypretreating the yarns at intervals along their length with anaqueous solution of sodium, hydroxide, making up a fabric containing said pretreated yarns, and completing the desired saponification of the pretreated areas by treating the fabrimwhile said yarns still contain reaction products derived from the pretreatment, with an aqueous solution of sodium acetate which has substantially no saponifying action on the areas of the material which have not been pretreated.

I ll,%

CERTIFICATE OF CORRECTION. Patent No. 2,108,856. February 22, 1938..

WILLIAM WHITEHEAD. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 2, strike out the word "part"; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of April, A. D. 1958.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

